private static void EncodeV4(Id3TagInfo tagInfo, TagContainer container)
{
TagDescriptorV4 descriptor = container.GetId3V24Descriptor();
tagInfo.Experimental = descriptor.ExperimentalIndicator;
tagInfo.ExtendedHeaderAvailable = descriptor.ExtendedHeader;
tagInfo.Unsynchronised = descriptor.Unsynchronisation;
tagInfo.HasFooter = descriptor.Footer;
if (descriptor.ExtendedHeader)
{
tagInfo.ExtendedHeader = ExtendedTagHeaderV4.Create(descriptor.UpdateTag, descriptor.CrcDataPresent,
descriptor.RestrictionPresent,
descriptor.Restriction, descriptor.Crc);
}
}
private byte[] BuildId3V4Tag(TagContainer tagContainer)
{
byte[] tagBytes;
var tag = tagContainer.GetId3V24Descriptor();
var frameBytes = GetFrameBytes(tagContainer);
//TODO: Implement CRC32 code here...
var extendedHeaderBytes = GetExtendedHeaderV4(tag);
var tagHeader = GetTagHeader(tagContainer);
//TODO: Implement Unsync Code...
tagBytes = BuildFinalTag(tagHeader, extendedHeaderBytes, frameBytes, 0,tag.Footer);
return tagBytes;
}
private static byte[] GetTagHeader(TagContainer tagContainer)
{
var tagHeader = new byte[10];
tagHeader[0] = 0x49;
tagHeader[1] = 0x44;
tagHeader[2] = 0x33;
switch (tagContainer.TagVersion)
{
case TagVersion.Id3V23:
var descriptorV3 = tagContainer.GetId3V23Descriptor();
tagHeader[3] = 0x03;
tagHeader[4] = 0x00;
if (descriptorV3.Unsynchronisation)
{
tagHeader[5] |= 0x80;
}
if (descriptorV3.ExtendedHeader)
{
tagHeader[5] |= 0x40;
}
if (descriptorV3.ExperimentalIndicator)
{
tagHeader[5] |= 0x20;
}
break;
case TagVersion.Id3V24:
var descriptorV4 = tagContainer.GetId3V24Descriptor();
tagHeader[3] = 0x04;
tagHeader[4] = 0x00;
if (descriptorV4.Unsynchronisation)
{
tagHeader[5] |= 0x80;
}
if (descriptorV4.ExtendedHeader)
{
tagHeader[5] |= 0x40;
}
if (descriptorV4.ExperimentalIndicator)
{
tagHeader[5] |= 0x20;
}
if (descriptorV4.Footer)
{
tagHeader[5] |= 0x10;
}
break;
default:
throw new ID3TagException("Unknown version!");
}
return tagHeader;
}
public void Write(TagContainer tagContainer, Stream input, Stream output)
{
if (input == null)
{
throw new ArgumentNullException("input");
}
if (output == null)
{
throw new ArgumentNullException("output");
}
if (tagContainer == null)
{
throw new ArgumentNullException("tagContainer");
}
//
// Validate whether the tag container is in ID3V2.3 formaz
//
string message;
var isTagValid = ValidateTag(tagContainer, out message);
if (!isTagValid)
{
throw new InvalidID3StructureException(message);
}
//
// OK. ID3Tag is valid. Let's write the tag.
//
byte[] tagBytes;
switch (tagContainer.TagVersion)
{
case TagVersion.Id3V23:
tagBytes = BuildId3V3Tag(tagContainer);
break;
case TagVersion.Id3V24:
tagBytes = BuildId3V4Tag(tagContainer);
break;
default:
throw new ID3TagException("This TagVersion is not supported!");
}
//
// encode the length
//
long length;
if (tagContainer.TagVersion == TagVersion.Id3V24)
{
var descriptor = tagContainer.GetId3V24Descriptor();
if (descriptor.Footer)
{
length = tagBytes.LongLength - 20;
}
else
{
length = tagBytes.LongLength - 10;
}
}
else
{
length = tagBytes.LongLength - 10;
}
var bits = GetBitCoding(length);
var lengthBytes = new byte[4];
EncodeLength(bits, lengthBytes);
Array.Copy(lengthBytes, 0, tagBytes, 6, 4);
//
// Build the tag bytes and start writing.
//
if (!input.CanRead)
{
throw new ID3IOException("Cannot read input stream");
}
if (!output.CanWrite)
{
throw new ID3IOException("Cannot write to output stream");
}
WriteToStream(input, output, tagBytes);
}
